Breech closure for firearms



Nov. 30, 1965 J. EDER BREEGH CLOSURE FOR FIREARMS Filed April 28, 1964 United States Patent 3,220,310 BREECH CLOSURE FOR FIREARMS Josef Eder, Dachau, Germany, assignor to Erma-Werke Waifenund Maschinenfabrik G.m.b.H., Dachau, Germany, a corporation of Germany Filed Apr. 28, 1964, Ser. No. 363,081 Claims priority, application Germany, Nov. 19, 1963, E 25,885 3 Claims. (Cl. 89-189) This invention is concerned with a type of breech closure for firearms in which the breech block is coupled to a closure toggle linkage, as in the known Maxey machine gun or the Luger pistol system (parabellum pistol).

Weapons of this character have been found extremely satisfactory in the range of calibres with which they have so far been used, but they are not useful with smaller bullet calibres, and thus with breech blocks of small mass. All experiments in this respect have failed because of the spring pressures which progressively increase during opening of the breech block and of the limited available mass of the block. Thus, in the case of all hitherto-known types of spring-actuated toggle breech closure system, account has to be taken of the fact that the closure spring is progressively loaded from the start of the opening of the breech, assumes its maximum closing force at the point of return of the breech block, and is progressively unloaded during the preliminary travel of the block, so that only the minimum power of the closure spring is effective 1 on the breech block when the latter is in its most forward position.

In addition to this, in all the known systems the arrangement has been that the toggle linkage is in its straightened condition when the breech block is in its closing position, the rear pivot point of the rear toggle being carried by a movable accommodating part connected to the barrel. During the opening of the breech, due to the return of the barrel of the weapon this part carries along the toggle linkage, still straightened at first in this condition until clamping projections, arranged at the joint between the two toggles, bring the toggle linkage into the collapsed condition as a result of their meeting fixed abutment surfaces on the weapon, for example on the butt of the pistol, thereby to tension the closure spring.

An object of this invention is to provide an improved toggle closure which overcomes the above drawbacks.

Another object of the present invention is to provide a toggle breech closure for weapons of the kind indicated which will function even with the smaller gas pressure which results from the use of a smaller bullet calibre (for example .22 calibre) and with the correspondingly small mass breech block.

In an advantageous form of the breech block closure for weapons, particularly pistols with a breech block, in accordance with this invention, the breech block is coupled to the closure spring through a toggle system comprising a rear toggle which is mounted on the casing or body of the weapon itself, for example on the butt of the pistol, and it is arranged that the toggle linkage shall still not have reached a straightened dead position when the breech block is in its closing position.

As a consequence, not only is the construction of the weapon simplified, but the breech block will be returned by smaller gas pressures.

In accordance with a further feature of the invention the rear toggle can be in the form of a bellcrank lever and have its free arm coupled to the closure spring.

Tests have shown that, given a suitable size and shape of bellcrank lever, the breech block moves under conditions which remain practically uniform at all times because the dynamic effects of the returning breech block and the forces developed by the loaded closure spring can be kept approximately uniform and constant, even where the loading and unloading of the closure spring take place progressively.

Reference is made to the accompanying drawings which illustrate the invention by way of example.

In these drawings:

FIGURE 1 schematically indicates in full lines the weapon closure system with the breech block in its closed position.

FIGURE 2 schematically illustrates the same with breech block open.

FIGURE 3 illustrates in more detail a weapon incorporating the system of the invention.

Referring to the drawings, the toggle linkage weapon closure, here depicted as applied to a pistol, comprises a front lever 2 which is pivotally connected to the breech block or chamber 1 at 1a, and a rear bellcrank lever 3. The two levers are pivotally coupled at 3a. The breech block 1 is slidably guided in the usual fashion on the body of the weapon and carries an extractor 6, a firing pin 7 with a spring 9, and an ejector 8 (FIGURE 3).

The bellcrank lever 3 is pivotally mounted at 3b on the butt 5 of the pistol, and is thus able to perform rocking movements during the forward and rearward travel of the block 1, but is unable to move in the same direction as this block.

When the breech block 1 is in the closed position illustrated in FIGURE 1, that is to say is applied against the barrel mouth or cartridge mounting 5a, the toggle linkage 2, 3 is in its closure or extended position but not a straightened dead position because the pivot point 3a remains above the line I-I joining the two pivot points 1a, 3b (see FIGURE 1). The closing spring element 4, which has only been diagrammatically represented and is of a known form, is pivoted to the free end of the bellcrank lever 3 at 30 and bears, on the other hand, against the butt 5 of the weapon at 512. The free arm of bellcrank lever 3 is, in this position, arranged so that the force of the closure spring element 4 acts substantially at right angles on the lever arm 3b, 3c.

The pistol illustrated is used in conventional fashion. A magazine containing cartridges arranged one on top of the other is placed in the butt of the pistol. For loading the toggle is retracted, and on release the chamber or breech block moves forward under the action of the closing spring element 4 and takes the upper cartridge out of the magazine and inserts it into the cartridge mounting in the barrel. The striking pin is released by actuating the trigger and fires the first cartridge. The resultant evolution of gas pushes the breech block back and produces the toggling action described above in which the toggle linkage is moved to the retracted position thereof. The empty cartridge case is at this time extracted and ejected. The forward and return movements of the chamber are performed automatically as the trigger is actuated.

When a shot has been fired the block 1 travels back to the position illustrated in FIGURE 2 and the pivot point 3a then moves into a position which is at a substantially higher level relatively to the connecting line II as compared with FIGURE 1. At the same time the pivot point 30 moves closer to the connecting line IIII, and loads the spring element 4, so that the lever arm 3b-3c is, in effect, shortened in relation to the line of action of the spring element 4. Thus, the moment consisting of the force of spring element 4 multiplied by the length of the lever arm 3-30 which is applicable at any time remains substantially the same for both positions of the block 1. Consequently, in contrast with the known types of construction there is no unfavorable effect on the breech closing action due to any progressive increase or decrease of the force of the spring element 4. Moreover, even when 3 the powder produces only a small gas pressure the block 1 is easily returned because of the pre-toggling of the linkage 2, 3, illustrated in FIGURE 1.

What is claimed is:

1. A firearm comprising a body, a barrel in said body having a mouth, a breech block slidably mounted on said body adjacent the mouth of said barrel, toggle linkage (means connected to said block and to said body and having extended and retracted positions for moving the breech block respectively between closed and open positions, and closure spring means connected to said linkage means and urging the latter to its extended position, said toggle linkage means comprising a front lever having a pivotal connection with said block, and a bellcrank lever pivotally connected to said front lever and having a pivotal connection with said body, the pivotal connection between the bellcrank lever and the front lever being disposed above a line joining the pivotal connection between the front lever and block and the pivotal connection between the bellcrank lever and the body when the linkage means is in extended position, the pivotal connection between the front lever and the bellcrank lever moving upwardly and away from said line as the linkage means moves to its retracted position, said closure spring means pivotally bearing against said body and having pivotal connection with the bellcrank lever at a location below a line joining the pivotal connection between the bellcrank lever and the body and the location where the closure spring means pivotally bears against the body such that as the linkage means moves to its retracted position, the spring means is compressed to increase the force by which it urges the linkage means to extended position whereas the line of action of said force is moved closer to the pivotal connection between the bellcrank lever and the body whereby the moment exerted by the spring means on the bellcrank lever tending to urge the linkage means to extended position remains substantially constant for all positions of the linkage means.

2. A firearm comprising a body, a barrel in said body having a mouth, a breech block slidably mounted on said body adjacent the mouth of said barrel, toggle linkage means connected to said block and to said body and having extended and retracted positions for moving the breech block respectively between closed and open positions, and closure spring means connected to said linkage means and urging the latter to its extended position, said toggle linkage means comprising a V-shaped bellcrank lever having first and second arms each with a remote end, said bellcrank lever being pivotally connected to said body at a location between the ends of the arms, a front lever having one end pivotally connected to the block and an opposite end pivotally connected to the end of one of the arms of the bellcrank lever, the latter pivotal connection being disposed above a line joining the pivotal connection between the front lever and the block with the pivotal connection between the bellcrank lever and the body when the linkage means is in extended position, the pivotal connection between the bellcrank lever and the front lever moving upwardly and away from said line as the linkage means moves to its retracted position, said closure spring means pivotally bearing against said body and having pivotal connection with the end of the other of the arms of the bellcrank lever, said closure spring means extending along a line joining the location where it pivotally bears against the body at its pivotal connection with the bellcrank lever such that as the linkage means moves to its retracted position the closure spring means is compressed and pivots about the location where it pivotally bears against the body to provide a substantially constant moment tending to urge the linkage means to extended position for all positions of the linkage means.

3. A firearm comprising a body, a barrel in said body having a mouth, a breech block slidably mounted on said body adjacent the mouth of said barrel, toggle linkage means connected to said block and to said body and having extended and retracted positions for moving the breech block respectively between closed and open positions, and closure spring means connected to said linkage means and urging the latter to its extended position, said toggle linkage means comprising a V-shaped bellcrank lever having first and second arms each with a remote end, pivotal means pivotally connecting the bellcrank lever to the body at a location between the ends of the arms, and front lever means pivotally connected to said block and to the bellcrank lever at the end of one of the arms thereof for pivotally moving the bellcrank lever about said body against the action of said spring means when the breech block is moved from closed to open position, said closure spring means pivotally bearing against said body and having pivotal connection with the end of the other of the arms of the bellcrank lever, said closure spring means extending along a line joining the location where it pivotally bears against the body at its pivotal connection with the bellcrank lever such that as the linkage means moves to its retracted position the closure spring means is compressed and pivots about the location where it pivotally bears against the body to provide a substantially constant moment tending to urge the linkage means to extended position for all positions of the linkage means.

References Cited by the Examiner UNITED STATES PATENTS 1,184,065 5/1916 Borchardt 89-l89 FOREIGN PATENTS 325,154 2/1930 Great Britain.

BENJAMIN A. BORCHELT, Primary Examiner.

FRED C. MATTERN, 111., Examiner, 

1. A FIREARM COMPRISING A BODY, A BARREL IN SAID BODY HAVING A MOUTH, A BREECH BLOCK SLIDABLY MOUNTED ON SAID BODY ADJACENT THE MOUTH OF SAID BARREL, TOGGLE LINKAGE MEANS CONNECTED TO SAID BLOCK AND TO SAID BOSY AND HAVING EXTENDED AND RETRACTED POSITIONS FOR MOVING THE BREECH BLOCK RESPECTIVELY BETWEEN CLOSED AND OPEN POSITIONS, AND CLOSURE SPRING MEANS CONNECTED TO SAID LINKAGE MEANS AND URGING THE LATTER TO ITS EXTENDED POSITION, SAID TOGGLE LINKAGE MEANS COMPRISING A FRONT LEVER HAVING A PIVOTAL CONNECTION WITH SAID BLOCK, AND A BELLCRANK LEVER PIVOTALLY CONNECTED TO SAID FRONT LEVER AND HAVING A PIVOTAL CONNECTION WITH SAID BODY, THE PIVOTAL CONNECTION BETWEEN THE BELLCRANK LEVER AND THE FRONT LEVER BEING DISPOSED ABOVE A LINE JOINING THE PIVOTAL CONNECTION BETWEEN THE FRONT LEVER AND BLOCK AND THE PIVOTAL CONNECTION BETWEEN THE BELLCRANK LEVER AND THE BODY WHEN THE LINKAGE MEANS IS IN EXTENDED POSITION, THE PIVOTAL CONNECTION BETWEEN THE FRONT LEVER AND THE BELLCRANK LEVER MOVING UPWARDLY AND AWAY FROM SAID LINE AS THE LINKAGE MEANS MOVES TO ITS RETRACTED POSITION, SAID CLOSURE SPRING MEANS PIVOTALLY BEAR- 